Dear Kristian, it is because of anatomy and biomechanics. Medial meniscus is more vulnerable to injury because of its anatomical attachments and pathomechanics involved in squatting. Lateral meniscus is attached with joint capsule so that it will be moved outward while we squatting. But medial meniscus trapped between bones during squatting. The weight through medial compartment will be increased with wider stance. In stance anterior horn is more vulnerable and as the flexion increases weight on meniscus will shift to posterior horn. So the optimal position for squatting is legs in shoulder width apart. Both too narrow and too wider stance are not biomechanically correct. Simple Answer to your question is wider stance will increase pain in medial meniscus.

Dear Kristian, it is because of anatomy and biomechanics. Medial meniscus is more vulnerable to injury because of its anatomical attachments and pathomechanics involved in squatting. Lateral meniscus is attached with joint capsule so that it will be moved outward while we squatting. But medial meniscus trapped between bones during squatting. The weight through medial compartment will be increased with wider stance. In stance anterior horn is more vulnerable and as the flexion increases weight on meniscus will shift to posterior horn. So the optimal position for squatting is legs in shoulder width apart. Both too narrow and too wider stance are not biomechanically correct. Simple Answer to your question is wider stance will increase pain in medial meniscus.

That's a great answer ! Thank you Kulandaivelan :-) 

Good answer Mr Kulandaivelan. I would like to highlight here the vulnerability of lateral meniscus is less because it is more mobile as there is no attachment to the joint capsule.

Hi Kristian, I also believe as Mr. Kulandaivelan, that a wider stance creates more load at the medial meniscus. The medial meniscus carries more load 60/ 65%) than the lat. meniscus. In wide stance the distribution changes to more medial load bearing.

But, there are no nerve fibers inside the meniscus- so how comes you feel pain, if attributing only the meniscus? Wider stance means also a slight rotation, shearing capsule/ ligg.- here there are nerve endings.

Thanks for all the great answer and your time! 

Hi Kristian. I am not familiar with the mechanics of weightlifting, or with the nature of the knee pain you describe. However, if there are no nerve fibres at the meniscii to feel pain as Jean says, this may indicate the pain is caused by another mechanism? It is probable that a wider stance in squat may require greater engagement of the abductors, and these attach at the inner knee. Perhaps this is worth considering? Do weightlifters usually consider their adductor muscles when training?

Hello Ian 

That could also be a thing to think about - because no, they don't train the adductors directly - but another discussion could be if the squat and the involvement of the adductors is enough. 

Dear Kristian, I would like to complete the information from Mr. 

Ian, you mean adductors I assume. Abductors do not attach at the ìnner knee. The pain is caused probably from structures as capsules, ligaments- if the pain is medial it means the medial structures are involved. :-)

Yes Jean. If you re-read what I wrote, you will see that is what I said. I think that the adductors would be more lengthened in a wider stance squat, and this might change the power required by the adductors when lifting the same weight.  I googled some diagrams on the anatomy of a weightlifting squat, and it looks as though the adductors could be an important contributor to the squat.  It would be useful if someone could model the forces on a computer.

As Jean says, the pain may be within the capsule or ligaments but these and the muscle attachments are all anatomically very close, are attached into the same areas, and might be affected by anatomical connections??

i agree totally with Dr. Iran Harvey

A study from researchers at the Department of Human Movement Science and Institute of Sports Sciences at Goethe-University in Germany demonstrated that the highest retropatellar compressive forces and stresses can be seen at 90°. During ATG full squats the large contact area of the patella with the femoral groove as knee flexion increases helps to dissipate compressive forces when this is combined with the increased force dissipation via thigh-calf contact force which is substantial measured at >30% bodyweight per leg, ATG squats do not cause injury but actually provide protection from injury by increasing anabolic metabolic processes and functional structural adaptations....... "There are no realistic estimations of knee-joint forces for knee-flexion angles beyond 50° in the deep squat. Based on biomechanical calculations and measurements of cadaver knee joints, the highest retropatellar compressive forces and stresses can be seen at 90°. With increasing flexion, the wrapping effect contributes to an enhanced load distribution and enhanced force transfer with lower retropatellar compressive forces.

Additionally, with further flexion of the knee joint a cranial displacement of facet contact areas with continuous enlargement of the retropatellar articulating surface occurs. Both lead to lower retropatellar compressive stresses. Menisci and cartilage, ligaments and bones are susceptible to anabolic metabolic processes and functional structural adaptations in response to increased activity and mechanical influences. Concerns about degenerative changes of the tendofemoral complex and the apparent higher risk for chondromalacia, osteoarthritis, and osteochondritis in deep squats are unfounded. With the same load configuration as in the deep squat, half and quarter squat training with comparatively supra-maximal loads will favour degenerative changes in the knee joints and spinal joints in the long term. Provided that technique is learned accurately under expert supervision and with progressive training loads, the deep squat presents an effective training exercise for protection against injuries and strengthening of the lower extremity. Contrary to commonly voiced concern, deep squats do not contribute increased risk of injury to passive tissues."

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